The present invention relates to a fuel injection valve for intermittent fuel injection into the combustion chamber of an internal combustion engine.
A fuel injection valve of this type is described in EP-A-0 426 205 in which a control element which is permanently connected to a housing and which has two end sides which lie opposite one another is arranged in said housing. An adjustable valve element bears, in its closed position, with a seat face against a seat face on the control element, which seat face is provided on an end side of the control element. A control passage which runs in the control element, from its one end side to its other end side is aligned with a throttle passage in the valve element. The throttle passage opens into a control chamber which is bounded by the control element and a control piston of an injection valve element. The control element is provided with a circumferential annular groove which is connected to a high pressure inlet formed in the housing for the fuel. Bores which are formed in the control element lead from the annular groove to the seat face of the control element. The valve element closes off these holes in its closed position. The control passage is connected via a throttle inlet in the control element to the annular groove in which the high pressure of the fuel is present. That end of the control passage which is located in the end side of the control element lying opposite the seat face is kept closed by the stem of a pilot valve.
If the pilot valve is activated, and the corresponding end of the control passage is thus cleared, the pressure in the control passage, in the throttle passage and in the control chamber drops quickly. The injection valve element moves away from its seat and clears injection openings.
The injection process is terminated by the closing of the one end of the control passage by the stem of the pilot valve. Fuel which is under high pressure flows via the throttle inlet in the control element to the control passage and acts on the valve element. The high pressure of the fuel which is present in the bores connected to the annular groove in the control element additionally acts on said valve element. This results in the valve element being briefly moved away from its closed position and clearing the bores in the control element. Fuel which is under high pressure can then flow via these bores into the control chamber. The pressure in the control chamber increases and brings about rapid closing of the injection valve element.
The known fuel injection valve has, inter alia, the disadvantage that it is costly to manufacture the control element.
The present invention is based on the object of providing a fuel injection valve of the described type which operates reliably while being simple to manufacture, and closes in each case with the smallest possible delay, and requires the smallest possible amount of fuel to control the opening and closing movement of the injection valve element.